Data and tools for profitability evaluation of measures for enhancement of the energetic quality of residential buildings – a contribution to RentalCal

Further improvements in the energetic quality of building stocks are a prerequisite to achieve objectives of conservation of resources and climate protection. In order to increase moderni-zation efforts, several obstacles need to be overcome at first. Here, one relevant topic amongst others is the analysis and evidence of the economic advantageousness of such measures. Besides a discussion of the methodical fundamentals to be applied, there are questions concerning the available data and the tools that need to be provided to the individual decision takers.

Several initial data are necessary to evaluate the profitability of measures for the improve-ment of the energetic quality of residential buildings. Hereto belong, among others, reliable da-ta regarding the amount of planning and construction expenditures as well as subsequent costs during the life cycle. During the early stages of planning, there are usually no specific offers by which the exact amount of financial effort could be determined. Planners and deci-sion makers oftentimes have to fall back on cost values from relevant literature that aren’t necessarily up-to-date or transparent. In this paper, current cost values and ranges for select-ed measures are presented and explained. They refer to the situation in Germany and are based on studies by IWU.

In practice, there are major price differences for the same measures. Thus, it makes sense to base profitability calculations on cost ranges. Likewise, depending on the specific local situa-tion, it has to be determined, which share in financial expenditure is attributable to a repair that was necessary anyway and which share is attributable to actual energetic improvements. Based on a calculation of equivalent energy prices, a simple tool for the profitability assess-ment of (retrofit) measures is presented. On one hand, it supports the handling of such rang-es, while on the other hand, it provides for an estimation of maximum financial expenditure until which profitability is still given (under the assumption of certain boundary conditions). It can be used for both the procurement of building services and dimensioning of funding pro-grammes.

The presented data and approaches contribute among others to the EU H2020 project RentalCal.